The present invention relates to a method and apparatus for the production of shatterproof, bulletproof and/or soundproof laminates consisting of two or more glass panes and shatter-, bullet- and/or soundproofing material between the panes. The invention also relates to the ultimate product, i.e., to laminates which can be produced in accordance with the method by resorting to the improved apparatus.
It is already known to produce soundproof laminates by introducing a mass of hardenable light-transmitting synthetic plastic material into the space or spaces between two or more spaced-apart light-transmitting glass panes. Such laminates exhibit a highly satisfactory resistance to penetration of sound. A drawback of presently known methods and apparatus is that they cannot guarantee complete expulsion of air from the space or spaces between neighboring panes; this affects the appearance as well as the soundproofing qualities of the product. Furthermore, presently known methods and apparatus cannot be resorted to for the mass-production of soundproof laminates, and they cannot insure uniform thickness of successively produced laminates and/or of each and every portion of a given laminate. As a rule, the median portions of the panes tend to bulge outwardly in response to admission of flowable (liquid) plastic material at a pressure which is sufficiently high to at least reduce the likelihood of development of air pockets in the spaces between neighboring panes.
Bulging of panes in laminates which are produced in accordance with heretofore known procedures is also attributable to the fact that the space between two neighboring panes receives liquid plastic material while the panes are held in vertical planes. The admitted material flows into the lower part of the space and its hydrostatic pressure suffices to effect an outward flexing of central portions of the panes.